1. Field of the Invention
The present invention relates generally to an internal combustion engine and more particularly to a swirl generating arrangement for an internal combustion engine which enables the controllable generation of swirl about the combustion chamber which will persist even to the end of the compression stroke.
2. Description of the Prior Art
In a known arrangement a vane has been disposed in the induction passage and arranged to be essentially parallel to the cylinder axis. This vane is movable to vary the cross sectional area of the induction passage and accordingly increase the velocity of the incoming charge under given operating conditions and direct the charge into the combustion chamber so as to swirl about the axis of the cylinder. However, this arrangement has suffered from the drawback that the variable opening through which the charge flows is substantially rectangular and oriented with the longitudinal axis thereof essentially parallel with the cylinder axis. This accordingly introduces the charge into the combustion chamber with a relatively weak flow component in the plane normal to the cylinder axis. This has lead to the formation of a swirl within the combustion chamber which all but disappears as the piston approaches TDC during the compression stroke, at which time the swirl has the most value in promoting efficient combustion.